HIGH PREVALENCE OF MUSCULAR VENTRICULAR SEPTAL-DEFECT IN NEONATES

Objectives. This study sought to use echocardiography to evaluate the prevalence of muscular ventricular septal defect in neonates. Backgrou nd. Ventricular septal defect is usually asymptomatic and closes spont aneously. An increase in its prevalence has been noted recently. One r eason is the improved detection of small defects, especially with the increased use of echocardiography. Therefore, one would expect a highe r prevalence in neonates on the basis of echocardiographic screening. Methods. Color Doppler echocardiography was performed in 1,053 consecu tive neonates 6 to 170 h old at Western Galilee Hospital, Israel. Data on the neonates, parents and family were obtained to analyze the infl uencing factors. The identified patients were followed up for 1 to 10 months or until ventricular septal defect closure. Results. Muscular v entricular septal defect was found in 56 (25 male, 31 female) of the 1 ,053 neonates, a prevalence of 53.2/1,000 live births. All neonates we re asymptomatic. Six had a systolic murmur. Electrocardiographic findi ngs were normal in 44 (97.8%) of 45 neonates followed up, and left ven tricular hypertro-phy occurred in 1 (2.2%). By echocardiography, 50 ve ntricular septal defects (89.3%) were single and 6 (10.7%) were multip le. The defects (range 1 to 5 mm in diameter, mean [+/-SD] 2.3 +/- 0.8 ) occurred anywhere along the muscular septum; 43 (76.8%) were detecta ble only on color Doppler imaging. The left atrium and left ventricle were mildly dilated. Of 45 neonates who were followed up for 6 to 10 m onths or until closure of the defects, 40 (88.9%) had defects that clo sed spontaneously. The risk of ventricular septal defect was not signi ficantly associated with gestational age, birth weight, birth order, m aternal age, diabetes, smoking, exposure to drugs or infection, patern al age, familial congenital heart disease, religion or consanguinity. Conclusions. There is a prevalence of muscular ventricular septal defe ct in neonates of 53.2/1,000 live births. The patients were asymptomat ic, and 88.9% had defects that closed spontaneously within 1 to 10 mon ths. These defects may be caused by environmental factors. In many cas es, muscular ventricular septal defect may also result from delayed ph ysiologic development.